Your Ultimate Guide to Two-Way Radio Definitions and Terminologies (A-Z)

An A to Z Encyclopedia of Essential Two-Way Radio Definitions
June 19, 2024 by
Your Ultimate Guide to Two-Way Radio Definitions and Terminologies (A-Z)
Expert Mobile Communications Ltd.
Two-way radios are essential tools for various industries, offering reliable communication in many environments. This guide provides a comprehensive overview of the key definitions and terminologies associated with two-way radios, ensuring you have a thorough understanding of these indispensable devices.

Key Definitions and Terminologies (A to Z)

  1. Analog Radio: Traditional radio technology that uses continuous signals to transmit voice.
  2. Antenna Impedance: The resistance of the antenna to the flow of electrical current, measured in ohms. Commonly 50 ohms for two-way radios.
  3. ASC (Automatic Squelch Control): A feature that automatically adjusts the squelch level to maintain optimal audio quality.
  4. Base Station: A fixed radio station used for communicating with mobile and portable radios. Base stations have higher power and better antennas, providing extensive coverage.
  5. Bluetooth Connectivity: Enables pairing with Bluetooth-enabled devices like headsets, providing enhanced convenience and functionality.
  6. Business Radios: Two-way radios designed specifically for professional use, offering features that support efficient communication in various business environments.
  7. CB (Citizens Band): A personal radio service in the 27 MHz band, used for short-distance communication.
  8. Channel Capacity: The maximum number of channels that a radio can store. Radios come in specified number of capacities: 8, 16, 128, 256, 512 or 1024 channels.
  9. Channel Spacing: The frequency separation between adjacent channels. Common spacings are 12.5 kHz and 25 kHz.
  10. Channels: A channel is a specific frequency that a two-way radio can tune into. Radios can have multiple channels, allowing users to switch frequencies to avoid interference and communicate with different groups.
  11. Commercial Radios: Robust two-way radios intended for use in commercial settings, providing durable and reliable communication for industries such as mining and manufacturing. Commer
  12. CTCSS (Continuous Tone-Coded Squelch System): A system that uses sub-audible tones to reduce interference by allowing only radios with the same tone to communicate.
  13. Desk Microphone: A stationary microphone often used with base stations for ease of use.
  14. Digital Radio: Modern radio technology that uses digital signals to transmit voice and data, offering improved audio quality and additional features.
  15. Dispatching Systems: Communication systems that coordinate and manage the dispatch of resources, personnel, and vehicles, often used in emergency services and logistics.
  16. Dispatch Operator: A professional responsible for coordinating and managing communication between field personnel and a central office, ensuring efficient deployment of resources and responding to emergency situations.
  17. DMR (Digital Mobile Radio): A digital radio standard offering improved audio quality, range, and spectrum efficiency.
  18. DPL (Digital Private Line): Another term for DCS, used to prevent unwanted transmissions on a radio channel.
  19. DCS (Digital-Coded Squelch): Similar to CTCSS but uses digital codes instead of analog tones to filter communications.
  20. Dual Mode: Radios that can operate in both analog and digital modes, providing flexibility.
  21. Electret Mic: A type of microphone that uses a permanently charged material to capture sound, common in two-way radios.
  22. Emergency Alert: A vital feature that allows users to send distress signals or alerts to other radios, ensuring prompt response in emergencies.
  23. Filter ANL (Automatic Noise Limiter): Reduces background noise caused by engine interference.
  24. Filter NB (Noise Blanker): Reduces pulse-type noise interference.
  25. FM (Frequency Modulation): A method of radio transmission where the frequency of the carrier wave is varied in accordance with the signal.
  26. FM Modulation: The process of varying the frequency of a carrier wave to transmit a signal.
  27. Footswitch: A pedal that allows hands-free operation of a radio's PTT function.
  28. FRS (Family Radio Service): A personal radio service using channels around 462 and 467 MHz in the UHF band, intended for short-distance, two-way communication.
  29. Frequency Band: A specific range of frequencies within the radio spectrum designated for a particular use or service.
  30. Frequency Range: The span of frequencies that a radio can operate within.
  31. Full-Duplex: Allows simultaneous two-way communication, similar to a phone conversation. Both parties can speak and listen at the same time.
  32. F.C.C. (Federal Communications Commission): The U.S. government agency responsible for regulating radio communications.
  33. GPS (Global Positioning System): A satellite-based system providing location and time information, often integrated into radios for tracking and navigation.
  34. GMRS (General Mobile Radio Service): A licensed radio service using frequencies around 462 and 467 MHz, offering higher power and greater range than FRS.
  35. Half-Duplex: A communication mode where transmission and reception occur on the same frequency but not simultaneously. Users must wait for the channel to be clear before responding.
  36. IP54: An ingress protection rating indicating resistance to dust and splashing water.
  37. IP68: An ingress protection rating indicating complete dust tightness and protection against continuous immersion in water.
  38. Illegal Radios: Communication devices that operate on unauthorized frequencies or exceed power limits set by regulatory authorities, often resulting in interference with legitimate radio services. Learn more about identifying illegal radios
  39. Intrinsically Safe: Equipment designed to operate safely in hazardous environments, preventing sparks and heat that could ignite flammable gases. Learn more
  40. Line of Sight: A direct, unobstructed path between the transmitting and receiving antennas. Line of sight is crucial for effective communication, especially for VHF radios.
  41. Man Down: A safety feature that sends an alert if the radio detects that the user has fallen or is immobile for a certain period.
  42. MHz (Megahertz): A unit of frequency equal to one million hertz. Used to define the frequency range of radios.
  43. MIL-STD 810H: A military standard for testing the durability and environmental resilience of equipment.
  44. Monitor: A function that opens the squelch, allowing the user to listen to all transmissions on a channel, even if they are weak or noisy.
  45. Mounting Bracket: A fixture used to secure a radio in a vehicle or other location.
  46. Noise Cancelling: A feature that reduces background noise, ensuring clearer communication.
  47. Omni-Directional: An antenna that radiates or receives signals equally well in all directions.
  48. Palm Microphone: A handheld microphone, often with a push-to-talk button, used with mobile radios.
  49. Programming Cable: A cable used to connect a radio to a computer for programming frequencies and settings.
  50. Pseudo Trunking: A method of dynamically allocating available channels to users, improving efficiency in radio systems.
  51. Push To Talk (PTT): A button on the radio that, when pressed, allows the user to transmit a message.
  52. Radio Programming: The process of configuring a radio with specific frequencies, channels, and settings via software.
  53. Repeater: A device that receives a signal on one frequency and retransmits it on another, extending the communication range of radios.
  54. Rx (Receive): The function of receiving a signal.
  55. Squelch: A function that mutes the audio output of a radio when the signal is below a certain threshold, reducing background noise.
  56. Talkback: Allows the user to hear their own transmission through the speaker, providing feedback that the radio is working.
  57. Trunking: A method of sharing a small number of radio frequencies among a large number of users, improving efficiency and reducing congestion.
  58. Tx (Transmit): The function of sending a signal.
  59. UHF (Ultra High Frequency) Radios: UHF refers to the frequency range of electromagnetic waves between 300 MHz and 3,000 MHz (3 GHz). Due to their shorter wavelength, UHF frequencies are ideal for use in and around buildings, as these waves penetrate walls and steel structures effectively. The UHF band also offers more available channels, reducing the likelihood of interference from other two-way radios in populated areas. UHF radios are particularly suitable for environments such as churches, medical offices, retail shops, hotels, casinos, and similar settings.
  60. VHF (Very High Frequency) Radios: VHF covers the frequency range from 30 MHz to 300 MHz. VHF signals travel closer to the earth's surface and are better suited for rural or open areas with fewer buildings and obstacles. VHF radios are ideal for "line of sight" applications where transmissions need to cover greater distances with minimal physical obstructions. Typical VHF radio users include boat operators on water and motorcycle riders looking to maintain communication on the road.
  61. VOX (Voice Activated Transmission): Allows hands-free operation by activating the radio when the user speaks, eliminating the need to press the PTT button. It is not advisable to use VOX Mode in noisy environments.
  62. Mobile/Vehicle Two-Way Radios: Radios designed for installation in vehicles, providing reliable communication for drivers and passengers while on the move.
  63. Portable/Handheld Two-Way Radios: Compact, battery-operated radios that can be easily carried by hand, suitable for use on the go.
  64. Push-to-Talk Over Cellular Radios: Devices that use cellular networks to enable instant, wide-area communication, combining the benefits of two-way radios with mobile phone technology.
  65. Watt: A unit of power. Higher wattage typically means greater transmission range.
  66. Zone: A group of channels programmed into a radio, often based on location or function.
  67. Zone Capacity: The maximum number of zones a radio can store. 


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